A measuring system is available for applying light to a test object so that photoacoustic waves (ultrasound waves) are generated from a measurement object in the test object due to photoacoustic effects and receiving the generated ultrasound waves by using an ultrasound probe with a hemispherical surface shape. The ultrasound probe with the hemispherical surface shape includes a plurality of ultrasound transducer elements which are arranged on an inner wall surface of the hemisphere.
Explanation will be provided with reference to FIG. 16. In FIG. 16, 10 denotes a test object, 11 denotes a light source, 12 denotes an ultrasound probe, 13 denotes ultrasound transducers, 21 denotes a light beam, 22 denotes photoacoustic waves (ultrasound waves), and 30 denotes an acoustic matching material. The ultrasound probe 12 has a hemispherical surface shape, and includes the plurality of ultrasound transducers 13 and the light source 11. The test object 10 is arranged in such a manner that part of the test object 10 is surrounded by the ultrasound probe 12 with the hemispherical surface shape. The acoustic matching material 30 is filled between the test object 10 and the ultrasound probe 12. Light 21 is applied from the light source 11 to the test object 10, and the photoacoustic waves (ultrasound waves) 22 generated at the test object are received at the plurality of ultrasound transducers 13 included in the ultrasound probe 12. Thus, an image of the test object is obtained.
PTL 1 discloses the above-mentioned ultrasound probe with the hemispherical surface shape. Such an ultrasound probe with the hemispherical surface shape may include a larger number of ultrasound transducers whose reception surface may be directed toward a certain measurement point than an ultrasound probe on a plane. Therefore, measurement of the test object may be achieved with a higher sensitivity.